Ethan has raised 60% of the money he needs to pay for his school trip. What percentage of the money does he still need to raise?
2 answers:
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Answer:
(1) The correct answer is option (a) 0.510
(2) The correct answer is option (b) = 0.9664
(3) The correct answer is option (a) 0.8665
Step-by-step explanation:
1. Find attached of question 1
2.
n= 850
p= 0.1400
here mean of distribution(μ) =n*p
=850* 0.1400
= 119
standard deviation σ = √(np(1-p))
= √(850*0.1400(1-0.1400))
= √102.34
=10.1163
for normal distribution z score =(X-μ)/σx
therefore from normal approximation of binomial distribution and continuity correction:
probability = P(X>100.5)
= P(Z>-1.83)
= 1-P(Z<-1.83)
= 1-0.0336
= 0.9664
3.
n = 1000
p = 0.08
mean of distribution(μ) =np
= 1000*0.08
= 80
and standard deviation σ=√(np(1-p))
= √(1000*0.08(1-0.08))
= √736
= 8.5790
probability = P(X>70.5)
= P(Z>-1.11)
= 1-P(Z<-1.11)
= 1-0.1335
= 0.8665
